Increasingly stringent emissions standards require vehicles powered by internal combustion engines, such as diesel engines, to be equipped with treatment systems to prevent and reduce harmful emissions being released to the atmosphere as by-products of combustion processes in systems such as diesel engines. Such treatment systems may include a variety of components, each of which is susceptible to failure. The failure or absence of one or more components of an exhaust treatment system may enable release of undesirable exhaust emissions and may waste or damage other related components of the treatment system. Accordingly, on board diagnostic (OBD) systems may be used to detect the operation and presence of components of the exhaust treatment system.
Existing OBD methods use a delta pressure sensor to diagnose the operation and potential failure of individual aftertreatment components. However, delta pressure sensors increase the complexity and costs of the exhaust system and diagnostic components.